something about gcc3.4.2

[usr.root]

i have done a test like this with gcc3.4.2:
int main(){

for(int i =0;i<3;i++);

return 0;
}
if i complile my code without using -std=c99,it shows a message :'for'
loop initial declaration used outside C99 mode .
i wonder that if not use -std=c99,which std it compile with?how can i
find that out?
(if i use -std=c99,it's ok)

 

[=?iso-8859-1?q?Dag-Erling_Sm=F8rgrav?=]

i wonder that if not use -std=c99, which std it compile with? how
can i find that out?

GNU C, which can be more or less accurately described as C89 with
extensions.

The problem with declarations in the initialization part of a for loop
is that GCC had a similar feature with slightly different semantics
before it was standardized. Code that relies on those semantics will
either not compile or produce different results with -std=c99, so the
GCC maintainers have decided to deprecate the old extension.

DES

 

[Skarmander]

GNU C, which can be more or less accurately described as C89 with
extensions.

The full story can be found in the GCC manual:
http://gcc.gnu.org/onlinedocs/gcc-3.4.5/gcc/C-Dialect-Options.html#C-Dialect-Options

S.

 

[Keith Thompson]

i have done a test like this with gcc3.4.2:
int main(){

for(int i =0;i<3;i++);

return 0;
}
if i complile my code without using -std=c99,it shows a message :'for'
loop initial declaration used outside C99 mode .
i wonder that if not use -std=c99,which std it compile with?how can i
find that out?
(if i use -std=c99,it's ok)

That's a question about gcc, not about the C language. You'll find
the answer in the extensive documentation that's provided with gcc.